Carton construction



y 8, 1965 J. w. BO YD ETAL 3,184,133

CARTON CONSTRUCTION Filed May :51, 1963 2 Sheets-Sheet l May 18, 1965 J, w. BOYD ETAL CARTON cousmucwxon 2 Sheets-Sheet 2 Filed May 51, 1963 United States Patent 3,184,133 CARTGN CONSTRUQTION James W. Boyd and Robert J. Allen, Crown Point, Ind,

assignors to Packaging Corporation of America, Evanston, IlL, a corporation of Delaware Filed May 31, 1963, Ser. No. 284,634 9 Claims. (Cl. 229--2.5)

This invention relates to a carton construction and more particularly to a molded pulp egg carton having an improved cover construction. The invention is particularly adapted for use with a 3 X 4 egg carton and is herein described in connection with a carton of this size. However, it is to be understood that features of the invention may be employed to substantial advantage in various other egg carton constructions such as, for example, the standard 2 X 6 carton.

It has long been common practice to construct molded pulp egg cartons having a cellular tray portion, a noncellular cover portion hinged to the back side of the tray so that it may be swung to a closed position overlying the tray and a latching means cooperating with the front side of the tray and cover so as to releasably maintain the cover in its closed position.

It has been found, however, that cartons of this type tend to exhibit certain peculiar characteristics during their manufacture, and that these characteristics are particularly evident in connection with the 3 X 4 cartons. This is due in part to the fact that in the noncellular cover therefor there is a substantial unsupported central area and during fabrication of the carton care must be taken in the handling of the wet product before it is sent to the dryer. In addition, because of this relatively large planar expanse there is a tendency for the cover to warp during drying, and while such warping is usually not severe, it is desirable to minimize it for purposes of appearance and facilitating any subsequent printing which may be done on the top and side surfaces of the carton and also for purposes of effecting a more positive locking of the cover in its closed position.

In addition, when molded egg cartons having covers with planar unsupported top surfaces are filled and stacked for storage or shipment, damage to the contents of the cartons frequently occurs by reason of buckling or sagging of the cover top surface; this is particularly true in the 3 x 4 carton. When such cover top surface is subjected to a load condition, which occurs when such cartons are arranged in stacked relation, the front panel or flange of the cover, which is flexible and unsupported except at its ends and across its top edge, has a tendency to bow outwardly. This tendency toward outward bowing is accentuated particularly when the carton becomes damp as might occur in refrigerated storage. Such outward bowing of the front panel may result in either complete disengagement of the cover from the latching flap or it may materially weaken the latching effect between the cover front panel and the front of the tray with the result that the cover may accidentally open during subsequent handling of the carton.

It is therefore one of the objects of this invention to provide a molded pulp carton having a cover construction which will materially improve the manufacturing, service and structural characteristics of the carton.

It is an additional object of this invention to provide a molded pulp carton having a strengthened cover which will permit stacking of loaded cartons for transportation, storage and/or display, while providing maximum protection for the contents of such stacked carton.

It is an additional object of this invention to provide a molded carton having a cover construction which will remain effectively latched in its closed position even when id hldd Patented May is, "i965 the carton is subjected to adverse environmental conditions such as high humidity.

It is an additional object of this invention toprovide a carton which is capable of accommodating articles of varying size and shape.

It is a further object of this invention to provide a novel cover construction for a molded pulp carton which will add considerable strength to the more fragile portions of the wet product from which the carton is molded so that the carton may be manufactured with greater ease, less waste and minimum warpage during drying thereof and thus produces a carton having a pleasing uniform geometric appearance.

Other objects may be seen and a further understanding of the invention may be had by referring to the following descripti n and claims taken in conjunction with the accompanying drawings.

In accordance with one embodiment of this invention, a molded pulp carton is provided which comprises a tray suitably partitioned to form a plurality of article receiv ing pockets; the partitioning means firmly and rigidly connecting the walls of the tray. The front wall of the tray has hingedly connected thereto a flap provided with latching formations or protuberances. A cover, hinged to the back wall of the tray, has a tOp surface, and front, back and end walls delimiting such surface. The cover front wall is apertured to accommodate the flap protuberances when the cover is in its closed position with respect to the tray and said flap has assumed a predetermined position of folded adjustment. In addition, the cover is provided with a hollow partitioning rib depending from and dividing the top surface into two sections of substantially like configuration. The rib is centrally disposed and extends between and rigidly interconnects the front and back walls of the cover. The rib, which is rectilinear and of substantially uniform configuration, increases the resistance of the top surface against ilexure, sag and/or warpage, and thus maintains the cover in its desired geometric configuration.

With reference to the drawings:

FIGURE 1 is a perspective view of one form of the improved carton showing the cover thereof latched in its closed position;

FIG. 2 is a top plan view of the carton shown in the form it would normally assume upon being removed from a mold cavity;

FIG. 3 is a sectional view of the carton taken along line 33 of FIG. 2;

FIG. 4 is a sectional view of the carton taken along line 44 of FIG.

FIG. 5 is a sectional view taken along line 55 of FIG. 4;

FIG. 6 is a fragmentary sectional view of the cover taken along line 6-6 of FIG. 3;

FIG. 7 is a fragmentary sectional view similar to FIG. 3, of a cover of modified construction;

FIG. 8 is a fragmentary sectional view taken along line 8-8 of FIG. 7;

FIG. 9 is a secti nal view, similar to FIG. 8, of a cover of further modified construction.

With more particular reference to the drawings, FIG. 1 illustrates a molded pulp carton Ml constructed in accordance with one embodiment of this invention and suitable for accommodating a dozen eggs or similar fragile articles. The illustrated carton is generally referred to in the trade as a 3 X 4 type; that is to say, the car-ton bottom or tray 12 is cellular and has a plurality of egg accommodating pockets 27 arranged in three rows of four pockets each. While the structural features of the present invention are herein-after described in relation to a 3 x 4 carton such invention is not limited thereto but may be readily incorporated in various other size and shaped molded cartons, e.g., a 2 x 6 type carton wherein the egg accommodating pockets thereof are arranged in two rows of six pockets each.

Besides a tray or bottom portion 12 and a cover or top portion 14, the illustrated carton It) includes a latching flap 16 which is foldably connected to the upper edge of the front Wall .18 of the tray. The tray 12 also includes a back wall 20 and a pair of spaced end walls 22 and 24 which connect the corresponding ends of said front and back walls. The upper edges of walls 18, 20, 22 and 24 terminate in an outwardly extending continuous planar ledge 12.

Extending upwardly from the bottom 26 of the tray and dividing same into twelve similar egg accommodating pockets 27 are two longitudinally extending partitioning ribs 28 and 3t and three transversely extending partitioning ribs 32, 34, and 36. At each of the six intersections of the transverse and longitudinally extending ribs there is formed a tapered post 38 which extends upwardly preferably to about the level of the ledge 12, see FIGS. 3 and 5. The longitudinal partitioning ribs 28 and 30 thus serve to rigidly tie together the end walls 22 and 24 of the tray while transverse partitioning ribs 32, 34 and 36 serve in a similar manner to rigidly tie together the front and back walls 18 and 20 of the .tray.

The cover 14 includes a pair of coplanar sections 40 and 42 which cooperate to form the top surface of the cover. The cover also includes a front wall 44, a rear wall 46 and a pair of end walls 48 and which interconnect the corresponding ends of the front and rear Walls. The rear wall 46 of the cover is foldably connected at 47 to the ledge 12 of the tray, see FIG. 2. Disposed between and separating top sections 40 and 42 and depending from the plane thereof into the concavity of cover 14 is an elongated hollow rib 52. The rib in the illu trated embodiment is disposed substantially equidistant from the cover end walls 48 and 50 and extends in a direction normal to the foldline 47. The rib 52 effects rigid connection between the front and rear walls 44 and 46, respectively. The partitioning rib 52 in its illustrated form is substantially V-sh-aped; however, the bottom or innermost portion 53 thereof may be rounded slightly so that the configuration of the rib in cross section approaches a U- shape.

The depth of the partitioning rib 52, as illustrated, measured in a direction normal tothe plane of top sections 40 and 42 is approximately the height of the cover walls 44, 46, 48 and 58; however, if desired, such depth may extend to approximately /2 the height of the cover walls. Normally, the rib depth approximates the height of the partitioning ribs 28, 30, 3-2, 34 and 36 for-med in the tray, see FIG. 3. By reason of the afore-noted depth of rib 52, the front and rear Walls 44 and 46 of the cover are rigidly tied together and thus the stiffness of the front wall is materially enhanced. Furthermore, the rib 52 provides added stiffness to the top surface of the cover and thus, minimizes buckling, sagging, or warping of the cover which might otherwise occur in a cover having a large unsupported planar area. Rib 52 is preferably of substantially uniform height and width.

If it is desired to increase the stiffness of rib 52 and thus overcome any tendency of the cover to bend or flex along the longitudinal axis of the rib as a fulcrum, a plurality of transversely disposed gussets 54 may be provided within the cavity of the rib. These gussets are integral with and interconnect the converging sides of the rib and may either be solid, see FIG. 6, or hollow 54, see FIG. 8. In the illustrated embodiment, see FIG. 1, two gussets are indicated; however, the number and spacing therebetween may vary from that as shown. Normally, when only two gussets are used one will be disposed adjacent each end of the rib. Where the gussets 54 are solid, see FIG. 6, they are formed during the vacuum molding operation by the pulp fibres from the slurry being drawn into and completely filling the narrow portions of the creen mold defining such gussets.

The gussets 54 or 54' may extend upwardly from the bottom 53 of the rib to the plane of the sections 40 and 42, although it is preferred that these gussets be of a height between /3 and the depth of the partitioning rib.

If desired, the gusset-s may be eliminated entirely as shown in FIG. 9, particularly where the pulp used in forming the carton is possessed of considerable resistance to tearing of the fibres.

Where solid gussets 54 are utilized, they erve to facilitate de-nesting of the cartons when a plurality of such cartons, disposed in the form shown in FIG. 2, are arranged in nested superposed relation. Nesting of a number of cartons in such a manner is customary when a large quantity of empty cartons are being transported or stored. The solid gussets in such a case prevent the rib of one carton cover becoming fully nested in the rib cavity of the cover of an adjacent carton.

The latching flap 16, as aforementioned, is hinged along line 17 to the ledge 12 of the tray. The foldlines 17 and 47, the latter being the cover foldline, are arranged in spaced parallel relation and remain in such. relation by reason of the rigid interconnection of the tray walls effected .by the partitioning ribs 28, 30, 32, 34, and 36 formed in the tray. The flap 16, when in operative position, assumes an upright position whereby it engages the rear surface of the cover front wall 44, see FIG. 4. The flap 16 is of lesser longitudinal extent than the front side 18 of the tray and is provided with a pair of longitudinally spaced protuberances 56 and 58. Extending inwardly from the free edge of the front flap 16 and disposed intermediate protuberances 56 and 58 is a center recess 60 which is of sufiicient size to accommodate without interference the underside of the partitioning rib 52 when the cover 14 is swung into its closed position, see FIG. 5.

When the cover is closed protuberances 56 and 58 are caused to resiliently project through a pair of correspond ing apertures 62 and 64, respectively, formed in the front wall 44 of the cover. By reason of the inherent resilient character of the molded pulp material, the flap protuberances 56 and 58 will snap into position through the cover apertures when they are aligned with the protuberances. It will be noted that apertures 62 and 64 are spaced below the plane of the top sections 40 and 42 so as to minimize the concentration of tearing stresses in the area of this juncture.

The perimetric portions 62a and 64a of apertures 62 and 64, respectively, which are disposed at the lower edges of the apertures, see FIGS. 4 and 5, are tapered or feathered during molding of the carton so that such portions are of reduced thickness. The reduced thickness of these perimetric portions permits positive locking of the cover in its closed position, notwithstanding that eggs or similar articles of varying size are accommodated within the tray pockets 27. In the case of eggs, it is common for the size thereof to vary considerably according to the breed, as well as the age of the chickens, and thus the improved carton is capable of compensating for this fact. Thus, when the oversized eggs or similar articles are being packed, the tops of the accommodated eggs will project a greater amount above the open side of the tray and will engage the inside surface of cover top panels 48 and 42 thereby preventing the cover from assuming its fully closed position. A fully closed position occurs when the outwardly projecting peripheral flange 14' of the cover substantially engages the peripheral flange 12 of the tray. When the cover cannot assume its fully closed position, that is to say, a gap occurs between the ledges 12' and 14' for a substantial extent thereof, the protuberances 56 and 58 of the latching fiap 16 are slightly out of alignment with cover apertures whereupon the protuberances cause collapse or rupture of the thinner perimetric portions 62a and 64a and effect enlargement of the apertures so as to permit such protuberances to readily pass therethrough, and lock the cover in a closed position with respect to the tray. When packing small (pullet) or medium size eggs in the carton,

the protuberances 56 and 58 will not cause collapsing of the aperture perimetric portion 62a and 64a because the protuberances will be fully aligned with the apertures.

While the illustrated improved carton shows a single reinforcing rib 52 in the cover which extends normal to the apertured front wall of said cover, additional reinforcing ribs may be utilized. Furthermore, the reinforcing rib may extend from the apertured wall of the cover to an end wall, if desired, or two reinforcing ribs could be used with the ribs extending from the apertured wall to both the adjacent cover walls. While the improved carton has been described in relation to molded pulp material, it is not to be limited thereto as other types of moldable material may be utilized, e.g., sheet of cellulose acetate, polystyrene, etc. All of these foregoing variations are deemed to come within the scope of the invention.

Thus, it will be seen that a carton constructed in accordance with this invention utilizes inexpensive molded pulp material and yet is possessed of superior structural characteristics. The partitioning rib, with or without the bracing gussets, minimizes materially, or in many instances eliminates entirely, the sag, buckling or warpage of the cover top surface which heretofore commonly occurred in covers having large unsupported planar areas. By reason of this fact, therefore, the molding and printing of the cover surfaces is greatly facilitated. The increased stilfness of the front panel of the cover caused by the elongated rib formed in the cover effects a more positive interlocking between the cover and latching fiap. In addition the improved canton is more versatile in accommodating eggs or similar articles varying in size and shape. Furthermore the partitioning rib provides a locating means for automatically aligning and closing the cartons during loading operation.

Although the invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made only by Way of example and that many additional modifications and changes in various details may be resorted to without departing from the spirit and scope of the invention as hereinafter claimed.

We claim:

1. A molded pulp carton comprising a cellular tray having a bottom, front, back, and end walls delimiting and extending upwardly from said bottom and defining an open upper side, and partitioning means disposed within the interior of said tray and cooperating with said walls and bottom to form a plurality of article-accommodating pockets and effect rigid interconnection between opposed walls of said tray; a cover hingedly connected to the upper edge of said tray back wall, said cover, when in one position of hinged adjustment, overlying, registering with, and closing the tray open upper side, said cover including a top surface delimited by front, back, and end walls which depend angularly outwardly from said top surface, an elongated continuous, rectilinear, hollow, inflexible rib disposed intermediate said cover end walls and depending from said cover top surface an amount less than the extent to which said front, back, and end walls depend therefrom, said rib rigidly interconnecting said cover front and back walls and retaining same in a substantially fixed relative position, the longitudinal axis of said rib being disposed substantially normal to the hinge axis of said cover, the ends of said rib being integral with said cover front and back walls, and rib reinforcing means disposed within the hollow of said rib and angularly positioned with respect to the rib axis and rigidly interconnecting depending hollow-forming portions of said rib, said cover front wall having a substantial portion thereof depending from the bottom of the rib integral with said front cover, said cover front wall being provided with an aperture spaced from the end of said rib integral with said front wall; and a latching flap hingedly connected to the upper edge T9 of said tray front wall and being provided with pro truding means projecting outwardly through said cover front wall aperture to effect locking of said cover in said closed position.

2. The molded pulp carton recited in claim 1 wherein the cover rib reinforcing means includes a solid gusset disposed within said hollow rib and having the ends of said gusset integral with the depending portions of said rib.

3. The molded pulp carton recited in claim 1 wherein the cover rib reinforcing means includes a pair of solid gussets, one gusset being disposed adjacent each end of said elongated rib, and being integral with the opposed depending portions of said rib.

4. A molded pulp carton comprising a tray having a bottom, front, back and end walls delimiting and extending upwardly from said bottom and defining an open upper side, and partitioning means disposed within the interior of said tray and cooperating with said walls and bottom to form a plurality of article-accommodating pockets, said partitioning means effecting rigid interconnection between the opposed walls of said tray; a cover mounted to overlie and register with the tray open upper side, said cover including a top surface, front, back, and end Walls delimiting and depending from said top surface, said cover back wall being foldably connected to the tray back wall, said cover front wall being apertured, and an elongated rib disposed intermediate said cover end walls and depending from said cover top surface and rigidly interconnecting said cover front and back walls; and a latching flap foldably connected to the upper edge of the tray front wall, said flap being provided with protruding means; said flap, when in one position of folded adjustment, having the protruding means thereof projecting outwardly through said cover apertured front wall to effect locking of said cover in overlying registered relation with respect to said tray open upper side; the perimetric portion of said cover front wall aperture which subtends the protruding means when the latter projects through said aperture being of reduced thickness and susceptible to rupture by said protruding means to effect enlargement of said aperture if said protruding means is slightly out of alignment with said aperture when said cover is initially moved to its overlying registered relation with respect to the tray open upper side.

5. A molded carton comprising a tray having upwardly extending interconnected Walls delimiting an open upper side, a cover mounted to overlie and register with the tray open upper side, and a latching flap hinged to the upper side of one of said tray walls, said latching flap being provided with protruding means; said cover including a top surface, downwardly extending interconnected walls delimiting said top surface, one of said depending walls being hinged to a tray wall other than the one to which said latching flap is hinged, a second of said cover depending walls being apertured whereby said latching flap protruding means projects outwardly through said apertured wall, when said flap is disposed in one position of hinged adjustment and said cover is in overlying registered relation with said tray open upper side; said cover being provided with an elongated continuous inflexible, hollow rib depending from said cover top surface an amount less than the extent to which said walls depend therefrom and rigidly interconnecting said apertured wall with one of the other of said cover walls, said elongated rib having a reinforcing gusset disposed within said rib hollow and positioned transversely with respect to the longitudinal axis of said rib and interconnecting the depending longitudinally extending hollowforming sides of said rib, said gusset having a height less than the depth of said rib, said cover second wall having a substantial portion thereof depending from the bottom of the rib connected to said cover second Wall.

6. The molded pulp carton recited in claim 5 wherein said gusset is solid.

7.'A molded pulp egg carton comprising an open top tray having front and back side walls interconnecting a pair of end walls, and partitioning means dividing said tray into a plurality of egg receiving pockets and rigidly tying said side and end walls together; a cover having a top panel delimited by depending front and back side panels, and a pair of end panels, and elongated continuous hollow inflexible rib depending from said top panel, said rib having the end limits thereof integrally connected to said cover front and back side panels and retaining same in a substantially fixed relative position, said rib forming said top panel into adjacent panel sections arranged in side by side relation, said rib depending from said top panel at least one-quarter but not more than substantially one-half the extent to which the side and end panels of said cover depend from said top panel, a pair of reinforcing gussets transversely disposed with respect to the rib axis and interconnecting opposed hollow-forming depending rib portions, the height of each gusset being less than the extent to which said rib depends from said top panel; and means cooperating with said cover and tray for releasably latching said cover in a closed overlying position with respect to the open top of said tray.

8. The carton structure recited in claim 7 wherein said adjacent top panel sections are of like configuration.

' 9. The carton structure recited in claim 7 wherein the height of each gusset is between one-third and twothirds the extent to which said rib depends from said cover top panel.

References Cited by the Examiner UNITED STATES PATENTS 2,655,303 10/53 Cox.

2,888,183 5/59 Reifers 229-29 FOREIGN PATENTS 800,949 9/58 Great Britain.

20 FRANKLIN T. GARRETT, Primary Examiner. 

1. A MOLDED PULP CARTON COMPRISING A CELLULAR TRAY HAVING A BOTTOM, FRONT, BACK, AND END WALLS DELIMITING AND EXTENDING UPWARDLY FROM SAID BOTTOM AND DEFINING AN OPEN UPPER SIDE, AND PARTITIONING MEANS DISPOSED WITHIN THE INTERIOR OF SAID TRAY AND COOPERATING WITH SAID WALLS AND BOTTOM TO FORM A PLURALITY OF ARTICLE-ACCOMMODATING POCKETS AND EFFECT RIGID INTERCONNECTION BETWEEN OPPOSED WALLS OF SAID TRAY; A COVER HINGEDLY CONNECTED TO THE UPPER EDGE OF SAID TRAY BACK WALL, SAID COVER, WHEN IN ONE POSITION OF HINGED ADJUSTMENT, OVERLYING, REGISTERING WITH, AND CLOSING THE TRAY OPEN UPPER SIDE, SAID COVER INCLUDING A TOP SURFACE DELIMITED BY FRONT, BACK, AND END WALLS WHICH DEPEND ANGULARLY OUTWARDLY FROM SAID TOP SURFACE, AN ELONGATED CONTINUOUS, RECTILINEAR, HOLLOW, INFLEXIBLE RIB DISPOSED INTERMEDIATE SAID COVER END WALLS AND DEPENDING FROM SAID COVER TOP SURFACE AN AMOUNT LESS THAN THE EXTENT TO WHICH SAID FRONT, BACK, AND END WALLS DEPEND THEREFROM, SAID RIB RIGIDLY INTERCONNECTING SAID COVER FRONT AND BACK WALLS AND RETAINING SAME IN A SUBSTANTIALLY FIXED RELATIVE POSITION, THE LONGITUDINAL AXIS OF SAID RIB BEING DISPOSED SUBSTANTIALLY NORMAL TO THE HINGE AXIS OF SAID COVER, THE ENDS OF SAID RIB BEING INTEGRAL WITH SAID COVER FRONT AND BACK WALLS, AND RIB REINFORCING MEANS DISPOSED WITHIN THE HOLLOW OF SAID RIB AND ANGULARLY POSITIONED WITH RESPECT TO THE RIB AXIS AND RIGIDLY INTERCONNECTING DEPENDING HOLLOW-FORMING PORTIONS OF SAID RIB, SAID COVER FRONT WALL HAVING A SUBSTANTIAL PORTION THEREOF DEPENDING FROM THE BOTTOM OF THE RIB INTEGRAL WITH SAID FRONT COVER, SAID COVER FRONT WALL BEING PROVIDED WITH AN APERTURE SPACED FROM THE END OF SAID RIB INTERGRAL WITH SAID FRONT WALL; AND A LATCHING FLAP HINGEDLY CONNECTED TO THE UPPER EDGE OF SAID TRAY FROM WALL AND BEING PROVIDED WITH PROTRUDING MEANS PROJECTING OUTWARDLY THROUGH SAID COVER FRONT WALL APERTURE TO EFFECT LOCKING OF SAID COVER IN SAID CLOSED POSITION. 